N-Hydroxysulfosuccinimide sodium salt is widely used in bioconjugation chemistry as a coupling agent. It is particularly effective in activating carboxyl groups for the formation of amide bonds with primary amines, making it essential in protein labeling, crosslinking, and immobilization processes. This compound is often employed in the preparation of antibody-drug conjugates, peptide synthesis, and the modification of biomolecules for diagnostic and therapeutic applications. Its water solubility and reactivity under mild conditions make it a preferred choice in various biochemical and biotechnological research applications.